Lionel F3s from the early to mid 2000s all have smoke units whether powered or not. That includes A and B units. They also all have one electro coupler and marker lights on the rear. Since each has its own radio board, no tether is needed and sound can easily be added to those lacking it. As Sam points out above the smoke units are much more reliable vs the newer ones. No nannies to shut them or the engine down. Three blinks? Forget about it. Worst case is the smoke resistor burns out. Sounds leave something to be desired but if smoke is your thing these are the ones to get.
Pete